Synthesis and antibacterial activity of water-soluble limonin benzoylhydrazone derivatives / 中国药科大学学报

@#As a compound rich in citrus plants, limonin has a wide range of biological activities, but its practical application is limited because of its poor water solubility.In this paper, eight new compounds 7a-7h were designed and synthesized by introducing benzoyl hydrazone at the carbonyl position of limonin.The results showed that the water solubilities of all compounds were higher than that of limonin, especially 7a, 7d, 7e and 7f.In addition, the experiment showed that compounds 7d and 7e with substituted hydroxyl groups at the interposition and para-position of the benzene ring had strong antibacterial effects against Escherichia coli and Staphylococcus aureus, and that compound 7e had the best activity, with minimum inhibitory concentrations of 0.31 mg/mL and 1.25 mg/mL, respectively.And compound 7e had better antibacterial activiy in E.coli than sodium benzoate.

Application of endovascular balloon occlusion in complex aortic surgery / 中华胸心血管外科杂志

Objective:To summarize the experience of 15 cases of balloon endovascular occlusion assisted aortic replacement.Methods:15 patients who needed reoperation after aortic surgery underwent endovascular balloon occlusion assisted aortic replacement by DSA guidance in the hybrid OR. Main inclusion criteria: The target vessel to be blocked cannot be directly blocked. Based on the last CTA before the operation, the diameter of the target vessel was measured, and the appropriate diameter balloon and the appropriate diameter balloon and the amount of contrast agent were selected. The vascular approach was selected according to the CTA.During the operation, the balloon was filled and fixed well, the distal invasive blood pressure waveform showed advection, and the pressure close to hydrostatic pressure as the complete blocking standard.Results:All 15 cases of balloon endovascular occlusion assisted aortic surgery were successful. After the operation, 14 target vessels normally without damage, and there was no vascular complication. One case after surgical three-branch stent surgery underwent the second thoracoabdominal aortic replacement operation. After the stent was blocked by the balloon, the new tissue in the stent fell off, and the celiac trunk and superior mesenteric artery were embolized for reoperation.Conclusion:Balloon endovascular occlusion technology expands the indications of aortic surgery and simplifies the operation, that is a safe and effective occlusion method. Whether the target vessel is suitable for balloon occlusion should be judged before the operation to avoid related complications.

Effect of Parkinson′s disease factor on sedative efficacy of dexmedetomidine / 中华麻醉学杂志

Objective:To evaluate the effect of Parkinson′s disease factor on the sedative efficacy of dexmedetomidine.Methods:The patients of either sex, aged 45-64 yr, of American Society of Anesthesiologists Physical Status classification Ⅱor Ⅲ, with body mass index of 18.5-30.0 kg/m 2, undergoing non-intracranial space-occupying lesions in neurosurgery, were selected.Patients were divided into control group (group C) and Parkinson′s disease group (group P) according to whether they had Parkinson′s disease or not.The ED 50 of dexmedetomidine was determined by using the Dixon′s up-and-down method.The initial dose of dexmedetomidine was 0.5 μg/kg in both groups, and each time the concentration increased/decreased by 0.05 μg/kg in the next patient, which was repeated until 7th independent crossover pair (loss of consciousness) appeared, and then the test was ended.The ED 50 and 95% confidence interval of dexmedetomidine inducing loss of consciousness were calculated using the probit test in a Logistic regression model.Hypertension, hypotension, bradycardia and nausea and vomiting were recorded. Results:Compared with group C, the ED 50 of dexmedetomidine inducing loss of consciousness was significantly increased in group P ( P<0.05), and no significant change was found in the incidence of adverse reactions in group P ( P>0.05). Conclusions:Parkinson′s disease factor can decrease the sedative efficacy of dexmedetomidine.

Effect of transcutaneous electrical acupoint stimulation on perioperative anxiety and postoperative pain in living kidney donors / 中华麻醉学杂志

Objective:To evaluate the effect of transcutaneous electrical acupoint stimulation (TEAS) on perioperative anxiety and postoperative pain in living kidney donors (LKDs).Methods:Seventy-two American Society of Anesthesiologists physical status Ⅰ or Ⅱ LKDs, aged 18-64 yr, with body mass index of 18-28 kg/m 2, undergoing living kidney transplantation, were selected, and divided into 2 groups ( n=36 each) using a random number table method: TEAS group (group T) and sham stimulation group (group S). In group T, TEAS was performed on the forenoon at 1 day before surgery (T 0), at 30 min before anesthesia induction on the morning of the operation day (T 1) and on the forenoon at 1 day after surgery (T 2) at bilateral Neiguan, Taichong and Yintang with a frequency 2-100 Hz, disperse-dense waves and current intensity 6-15 mA, and each TEAS lasted for 30 min.Only electrode patches were applied at the same acupoint and at the same time point, but no stimulation was applied in group S. In T and S groups, brachial venous blood samples were collected before each stimulation for measurement of the plasma 5-hydroxytryptamine (5-HT) concentration.The Hospital Anxiety Depression Scale-Anxiety subscale (HADS-A) scores at T 0, T 1, T 2, on day 3 after surgery (T 3) and before discharge (T 4) in the 2 groups were recorded.The consumption of anesthetics during operation, laryngeal mask airway removal time, requirement for rescue analgesia within 72 h after surgery and the development of postoperative complications were recorded.The LKDs were followed up by telephone at 3 months after surgery (T 5) to record the scores of HADS-A and Leeds Assessment of Neuropathic Symptoms and Sign (LANSS) scale. Results:Compared to group S, the incidence of anxiety was significantly decreased T 1, T 2 and T 3, the incidence of rescue analgesia within 72 h after surgery was decreased, plasma concentration of 5-HT was increased at T 1 and T 2, the incidence of postoperative nausea and vomiting was decreased, and the time to first flatus was shortened in group T ( P<0.05). There was no significant difference in the consumption of anesthetics during operation, laryngeal mask airway removal time, and the incidence of anxiety and neuropathic pain within 3 months after surgery between the 2 groups ( P>0.05). Conclusion:TEAS can relieve early preoperative and postoperative anxiety and alleviate postoperative pain in LKDs.

Effect of gender on neuromuscular blockade of rocuronium in epileptics / 中华麻醉学杂志

Objective:To evaluate the effect of gender on neuromuscular blockade of rocuronium in epileptics.Methods:Forty American Society of Anesthesiologists physical status Ⅱ or Ⅲ patients, aged 18-59 yr, with body mass index of 18.5-24.0 kg/m 2, scheduled for elective surgery for treatment of epilepsy under general anesthesia, were divided into 2 groups ( n=20 each) according to gender: male group (group M) and female group (group F). Neuromuscular conduction function was monitored with a muscle relaxation monitor.Ulnar nerve was stimulated in TOF mode (frequency 2 Hz, wave width 0.2 ms, stimulation current 70 mA and interval 12 s). Rocuronium 0.8 mg/kg was injected intravenously during anesthesia induction, and endotracheal intubation was performed when T l reached maximum inhibition.The conditions of endotracheal intubation were evaluated by the modified method.When T 1 recovered to 25% during operation, rocuronium 0.15 mg/kg was intravenously injected.Sugammadex sodium 2 mg/kg was injected intravenously when T 1 recovered to 50% after surgery.The onset time (T onset), peak time (T peak), 10% recovery time (T 10%), 10%-25% recovery time (T 10%-25%), 25%-50% recovery time (T 25%-50%), 50%-75% recovery time (T 50%-75%) and 75%-90% recovery time (T 75%-90%) of rocuronium were recorded.Peripheral venous blood samples (3 ml) were collected when T 1 recovered to 25% and 75%, and the concentration of rocuronium was detected by liquid chromatography-tandem mass spectrum.The consumption of rocuronium per unit of weight per minute was calculated. Results:There was no significant difference between the two groups in terms of T onset, T peak, T 10%, T 10%-25%, T 25%-50%, T 50%-75%, T 75%-90%, endotracheal intubation conditions, blood concentration of rocuronium at varied time points, or consumption of rocuronium per unit of weight per minute ( P>0.05). Conclusion:Gender exerts no effect on the neuromuscular blockade of rocuronium in epileptics.

Structure and mechanical characteristics of spinal dura mater in different segments of sheep's spine / 中国修复重建外科杂志

Objective: To clarify the structure and biomechanical characteristics of the dura mater of the cervical, thoracic, and lumbar segments of sheep, in order to provide a theoretical reference for the study of artificial dura mater. Methods: Five adult male white sheep were sacrificed. The dura mater of C 5, T 10, and L 3 planes were obtained. The histological HE staining was used to observe the internal structure and the thickness of dura mater; the inner and outer surfaces morphology of the dura was observed by scanning electron microscopy (SEM); transmission electron microscopy (TEM) was used to observe the internal structure of dura mater and to measure the diameter of collagen fibers in each part of dura mater. The dura mater of C 6, C 7, T 11, T 12, L 4, and L 5 planes were taken for uniaxial biomechanical test, and modulus of elasticity, tensile strength, and elongation at break were measured. Results: HE staining showed that the thickness of the cervical, thoracic, and lumbar dura mater gradually decreased, and the thickness of the dura mater was (268.19±15.91), (198.16±27.25), (103.74±21.54) μm, respectively, and the differences were significant ( P0.05). Uniaxial biomechanical tests results showed that there was no significant difference in modulus of elasticity, tensile strength, and elongation at break between the axial and transverse dura mater of the cervical dura mater ( P>0.05); the axial data of thoracic and lumbar segments were significantly larger than the transverse data ( P0.05). Conclusion: The thickness of dura mater in sheep decreased gradually from head to tail. There are more collagen fibers and fewer cells on the inner surface of dura mater, while the outer surface of dura mater is covered by cells. The collagen fiberboard layers in the dura mater are arranged alternately, and have obvious anisotropic biomechanical characteristics, and the anisotropic biomechanical characteristics get more significant from the head to the tail.

Effect of Olfactory Mucosal Neural Stem Cells on Neuronal Apoptosis in Rats / 中国康复理论与实践

@#Objective To investigate the effect of olfactory mucosal neural stem cells (OM-NSCs) on neuronal apoptosis in rats. Methods OM-NSCs were isolated from adult male Sprague-Dawley rats, and neurons were isolated from fetal Sprague-Dawley rats. The neurons were divided into blank group, control group and experiment group after culture in vitro, which were further cultured in nomal, cultured in nomal 24 hours after stimulation of interleukin-1β (IL-1β), and cultured with OM-NSCs 24 hours after stimulation of IL-1β, respectively, for 24 hours. The apoptosis of neurons was observed with double staining of TUNEL and microtubule-associated protein 2 antibodies. Results There were few apoptotic cells in the blank group, and very many in the control group; the apoptotic cells were fewer in the experiment group than in the control group (F=39.764, P<0.01).Conclusion OM-NSCs can significantly inhibit neuronal apoptosis, which may play a role in neuroprotection.

Advance in Metabolomics of Spinal Cord Injury (review) / 中国康复理论与实践

@#Spinal cord injury (SCI) often causes different degrees of sensory and motor dysfunction, resulting in permanent disability, with many complications and difficult to cure. Metabolomics, as a new developing technique, identifies specific biomarkers for diagnosis, treatment or prognosis judgement by analyzing the changes in the metabolites after individual stress, and can make the best treatment and rehabilitation program for the patients in the early stage of the disease. At present, some achievements have been made in the diagnosis, treatment and prognosis monitoring of spinal cord injury, and some potential biomarkers have been identified. However, the pathophysiology of spinal cord injury is not fully understood, and relevant biomarkers are also lacking in clinical trials.

Effects of superior laryngeal nerve block combined with intratracheal surface anesthesia on stress response in elderly hypertensive patients undergoing double-lumen tracheal intubation / 临床麻醉学杂志

Objective To observe the effects of ultrasound-guided laryngeal nerve block combined with intratracheal surface anesthesia on the intubation reaction of double-lumen endotracheal tube in elderly hypertensive patients.Methods Sixty elderly hypertensive patients,including 37 males and 23 females, with ASA physical statusⅡor Ⅲ,aged 65-85 years,scheduled for thoracic surgery under general anesthesia requiring one-lung ventilation,were equally and randomly divided into either laryngeal nerve block combined with intratracheal surface anesthesia group (group S)or general anesthesia group (group C).Internal jugular vein blood samples were taken to measure the plasma concentrations of epinephrine (E)and norepinephrine (NE) when patients entering the operating room (T0 ),before intubation (T1 ),immediately after intubation (T2 ),at 1 min (T3 ),3 min (T4 ),5 min (T5 )and 10 min (T6 )after intubation.Adverse e-vents,such us hypertension and tachycardia,were recorded during induction and intubation.Results Com-pared with T0 ,the plasma concentrations of E and NE were significantly increased at T2-T5 in group C (P<0.05 or P <0.01),while there were no such significant changes in group S.The plasma concentration of E and NE at T2-T5 in group S were significantly lower than that in group C (P <0.05 or P <0.01).The incidence of hypertension in group S was significantly lower than that in group C during induction of intuba-tion (0% vs 37%,P <0.01).There were no hypotension,tachycardia and bradycardia during induction and intubation in both groups.Conclusion Ultrasound-guided laryngeal nerve block combined with intratra-cheal surface anesthesia can effectively inhibit the intubation reaction of double-lumen endotracheal tube in elderly hypertensive patients,which is helpful for maintaining the hemodynamic stability during anesthesia induction.

Observation of the effect of percutaneous transforaminal endoscopic surgery for lumbar prolapse upwards type disc herniation / 中国基层医药

Objective To investigate the effect of percutaneous transforaminal endoscopic surgery for lumbar prolapse upwards type disc herniation.Methods According to the digital table,90 patients with lumbar prolapse upwards type disc herniation were randomly divide into the observation group and the control group,45 cases in each group.The observation group was treated with percutaneous transforaminal endoscopic surgery,the control group was treated with conventional open surgery.The curative effect,operation and adverse reactions were compared between the two groups.Results All patients were satisfied with the location,and they were completely removed from the nucleus.Compared with the control group,the operation time[(75.3±23.1)min vs.(103.4±35.4)min]and hospitalization time[(6.8±1.2)d vs.(8.7±1.8)d]of the observation group were shorter,the bleeding volume[(24.5±8.5)mL vs.(51.6±12.7)mL]was lower,the differences were statistically significant(t=4.453,5.632,4.269,all P0.05).ConclusionPercutaneous endoscopic discectomy surgery in the treatment of lumbar prolapse upwards type disc herniation is reliable,and it has less trauma and shorter hospital stay.

Median effective target plasma concentration of remifentanil inhibiting responses to skull-pin placement when combined with propofol in female patients undergoing neurosurgery / 中华麻醉学杂志

Objective To determine the median effective target plasma concentration (EC50) of remifentanil inhibiting responses to skull-pin placement when combined with propofol in the female patients undergoing neurosurgery.Methods Sixteen female patients,aged 20-60 yr,with body mass index of 18-30 kg/m2,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,scheduled for elective neurosurgery under general anesthesia,were enrolled in this study.Anesthesia was induced with propofol and remifentanil given by target-controlled infusion and iv rocuronium 0.6 mg/kg.The target plasma concentration (Cp) of remifentanil and propofol was set at 5 ng/ml and 3 μg/ml,respectively.At 3 min after tracheal intubation,the target Cp of remifentanil was adjusted and set at 5 ng/ml in the first patient.The skull-pin was placed after the target effect-site and plasma concentrations were balanced.The Cp increased/decreased by 20％ each time in the next patient depending on whether or not the response to skull-pin placement was positive.The ratio between the two successive concentrations was 1.2.The response to skull-pin placement was defined as positive when heart rate and/or mean arterial pressure increased by 20％ of the baseline value within 1 min after placement.The EC50 and 95％ confidence interval of remifentanil required to inhibit responses to skull-pin placement were calculated when combined with propofol.Results The EC50 (95％ confidence interval) of remifentanil required to inhibit responses to skull-pin placement was 3.74 (3.43-4.09) ng/ml when combined with propofol.Conclusion When combined with propofol,the EC50 of remifentanil inhibiting responses to skull-pin placement is 3.74 ng/ml in the female patients undergoing neurosurgery.

Changes in expression of spinal endothelin-1 and its receptors in a mouse model of bone cancer pain / 中华麻醉学杂志

Objective To evaluate the changes in the expression of spinal endothelin-1 (ET-1) and its receptors in a mouse model of bone cancer pain (BCP).Methods Ninety-six healthy male SPF C3H/HeN mice,aged 4-6 weeks,weighing 20-25 g,were divided into 2 groups (n=48 each) using a random number table:sham operation group (group S) and BCP group.BCP was produced by injecting α-MEM 20 μl containing 1×104 cells/μ1 NCTC 2472 osteosarcoma cells into the distal medullary cavity of the right femur bone.In group S,t-MEM 20 μl was injected into the distal medullary cavity of the right femur bone.Mechanical paw withdrawal threshold (MWT) and the number of spontaneous flinches (NSF) were measured on 1 day before inoculation (T0) and 4,7,10,14 and 21 days after inoculation (T1-5).Twelve mice of each group were randomly sacrificed at T0,2,4,5,and the lumbar enlargement segments of the spinal cord were harvested to detect the expression of ET-1,endothelin type A receptor and endothelin type B receptor protein and mRNA (using Western blot or real-time polymerase chain reaction).Results The MWT was significantly lower and the NSF was higher at T1 in group S and at T1-5 in group BCP than at T0 (P＜0.05).Compared with group S,the MWT was significantly decreased and the NSF was increased at T2-s,and the expression of ET-1,endothelin type A receptor and endothelin type B receptor protein and mRNA was down-regulated at T2,4,5 in group BCP (P＜0.05).Conclusion The pathophysiological process of BCP is associated with down-regulating the expression of spinal ET-1 and its receptors in mice.

Effect of transcutaneous electric acupoint stimulation on prognosis in patients at high risk of postop-erative pulmonary complications / 中华麻醉学杂志

Objective To evaluate the effect of transcutaneous electric acupoint stimulation (TEAS)on prognosis in the patients at high risk of postoperative pulmonary complications. Methods Sixty American Society of Anesthesiologists physical statusⅡorⅢpatients of both sexes, aged 65-72 yr, with body mass index of 18-25 kg∕m2, scheduled for elective thoracoscopic and laparoscopic radical resection of e-sophageal cancer, were divided into placebo control group(group C, n=30)and TEAS group(n=30). In group TEAS, bilateral Zusanli(ST36), Hegu(LI4)and Feishu(BL13)acupoints were stimulated for 30 min(disperse-dense waves, frequency 2∕100 Hz, intensity of currents 8-12 mA)starting from 30 min be-fore anesthesia induction.In group C, electrodes were placed on the same acupoints before anesthesia induc-tion, but no current was given.General anesthesia was performed in two groups.Before one-lung ventilation, at 30 min and 2 h of one-lung ventilation and at 1 h after operation(T1-4), blood samples were drawn from the radial artery for blood gas analysis, and oxygenation index and alveolar-arterial oxygen partial pressure difference were calculated.Blood samples were collected from the internal jugular vein at T1-3and 24 h after surgery(T5)for determination of plasma tumor necrosis factor-alpha, interleukin-6(IL-6)and IL-10 con-centrations.The development of postoperative pulmonary complications, time for removal of drainage tube and length of hospital stay were recorded. Results Compared with group C, the oxygenation index at T2-4and plasma IL-10 concentrations at T3were significantly increased, the alveolar-arterial oxygen partial pressure difference at T2,3, plasma tumor necrosis factor-alpha concentrations at T2,3, plasma IL-10 concentrations at T3,5and incidence of postoperative pulmonary complications were decreased, and the time for removal of drainage tube and length of hospital stay were shortened in group TEAS(P<0.05). Conclusion TEAS can improve prognosis in the patients at high risk of postoperative pulmonary complications.

Effects of Danshensu on bone formation in ovariectomized rats / 浙江大学学报·医学版

To investigate the effects of Danshensu on bone formation in ovariectomized rats.Thirty female SD rats were randomly divided into three groups with 10 rats in each:blank control group, model control group and Danshensu group. The osteoporosis model was induced by bilateral ovariectomy and rats in Danshensu group were fed with Danshensu 12.5 mg·kg·dby gavage after ostroporosis model induced. All animals were sacrificed after 90 days. The bone mineral density (BMD) of the whole body, femur and lumbar vertebra was measured by dual energy X-ray absorptiometry. The biomechanical properties of femur were measured by AG-IS mechanical universal testing machine. Serum osteocalcin and bone alkaline phosphates (BALP) levels were measured by ELISA. The number of osteoblasts of proximal femoral metaphysis was counted with light microscopy after HE staining.Compared with blank control group, BMD, biomechanical properties of femur, serum osteocalcin and BALP levels and the number of osteoblasts were decreased in model control group (<0.05 or<0.01). While compared with model control group, BMDs of the whole body, femur and lumbar vertebra, the elastic modulus, maximum load, yield strength, breaking point load of femur, the serum levels of osteocalcin and BALP, and the number of osteoblasts were significantly improved in Danshensu group (<0.05 or<0.01).Danshensu can improve bone quality by increasing bone density, improving biomechanical properties, promoting the expression of osteogenesis-related factors, and increasing the number of osteoblasts.

Research of λ-cyhalothrin affect synaptic development in hippocampus by interfering with estrogen action / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effects of λ-cyhalothrin on hippocampus by interfering with estrogen.</p><p><b>METHODS</b>The healthy female ICR mice of postnatal 28 days were random divided into 12 groups, 4 of those were sham-operation include control, λ-cyhalothrin (LCT, 3.0 µg/g), Letrozole (Let, 1.0 µg/g), and LCT (3.0 µg/g)+Let (1.0 µg/g); and the last 8 were ovariectomized include OVX, Estradiol (E2, 10.0 µg/g), LCT, Let, E2+LCT, E2+Let, LCT+Let, E2+LCT+Let. 10 mice in every group received drugs by intraperitoneal injection for 2 days. Then half of every group initiate the ethological test (open field test and Morris water maze) 24 h later. The last half animals were sacrificed to made frozen section for immunofluorescent assay of postsynaptic density protein 95 (PSD95).</p><p><b>RESULTS</b>In ethological test, campared with Sham, OVX can lengthen incubation period in the first grid and to get on the platform (P < 0.05); campared with OVX, OVX+E2 can increase the total numbers of through grid and shorten the incubation period to get on the platform (P < 0.05); campared with OVX+E2, OVX+E2+LCT can reduce the number of grid and standing, lengthen incubation period to the platform (P < 0.05); campared with Sham, Sham+LCT can lengthen incubation period to the platform of Sham mice (P < 0.05), but campared with OVX, OVX+LCT can shoten incubation period in the first grid and to get on the platform in OVX mice (P < 0.05); campared with Sham+Let, Sham+LCT+Let can lengthen incubation period in the first grid, reduce the the number of grid and standing (P < 0.05). In the Immunohistochemical fluorescence experiment we find that, campared with Sham, OVX can reduce the expression of PSD95 in CA1,CA3 and DG (P < 0.05); however campared with OVX, E2 or LCT can both inhibit the effect of OVX (P < 0.05); campared with Sham, Sham+LCT can reduce the expression of PSD95, the same result when OVX+E2+LCT campared with OVX+E2 (P < 0.05); campared with OVX+E2+Let, OVX+E2+LCT+Let can reduce the expression of PSD95 in CA3 (P < 0.05); campared with OVX+Let, OVX+LCT+Let can increase the expression of PSD95 in DG (P < 0.05).</p><p><b>CONCLUSIONS</b>When few estrogen exist in the body, LCT can show estrogen-like action to promote hippocampal synaptic development; but when circulating estrogen exist, LCT can inhibit synaptic development by interfering estrogen.</p>

Effect of injection of luzindole-a receptor of melatonin on spine development of chickens / 中国矫形外科杂志

[Objective]To observe the growth of the spine of chickens after injection of the antagonist of the MEL1-a receptor of melatonin to restrain the effect of melatonin. [Methods]Forty-five newborn Little-Shaoxing chickens were divided in three groups:(1) Fifteen chickens(control group) were kept in light-dark(12h: 12h) cycle,500 1x in daytime and 0-5 1x in nighttime.(2) Fifteen chickens(operative group) received pinealectomy when they were 3 days old.They were kept in the same light condition as the control group.(3) Fifteen chickens(antagonist group),a antagonist of the MEL1-a receptor of melatonin(Luzindole,30mg/kg) was injected abdominally every day when they were 3 days old.They were kept in the same light condition as the control group.Radiologic examinations were performed for all chickens.[Results]No chickens developed scoliosis in control group and antagonist group.Seven chickens developed scoliosis in the operative group when the chickens were 3 months old.[Conclusion]Pinealectomy can reduce the secretion of melatonin and induce scoliosis in some of the chickens.But injection of Luzindole to restrain the effect of malatonin cannot induce experimental scoliosis in chickens.

Three-dimensional finite element analysis of two and three cannulated hip screws fixation for adductive femoral neck fractures / 中国矫形外科杂志

[Objective]To explore the biomechanical stability of fixation with two and three cannulated compression screws in treatment of the adductive femoral neck fractures by the three-dimensional finite element analysis(FEA).[Method]Two FEA models of two screws and three screws for adductive femoral neck facture fixations were set up to investigate the simulated loading of three different conditions.[Result]At the condition of the heel touching the ground and the middle position,there was no difference in the biomechanical stabilities of the two models.However,at the condition of the tiptoe departing from the groud,the model of three screws fixation was better in torsion resistance and stretching resistance.[Conclusion]The biomechanical stability of fixation with two screws is determined by the direction of loading.Three cannulated compression screws fixation provides better biomechanical stability.